US3544471A - Piezoelectric ceramics - Google Patents

Description

DH'- 1, 1970 4Momo TsuBoucl-'n ETAL 3,544,471

PIEZOELECTRIC CERAMICS Filed July 9, 1969 v 5 Sheets-Sheet 1 FIG! F 2 ,.INVENTORS Namo rsuavoucm Mns/m Vmmuuxsm roMeJl o u l A TTORNEYS DOG 1, 19'",l Momo 'rsuaoucm Erm. 3,544,471

rmzomzonrc cmwncs Filed July s.' 1969 5' sheets-sheet a FIGB FIG. 6

' I N VENTORS v NORIQ TSUBOUC H l MSAO TAKAHSHI Iomega anno su o AKAsul J3@ Mw@ Dec. l, 1970 uomo rsuaoucHl ETAI- 3,544,471

vPzfrzzolnracrrxuc CERAMICS +G. wt ya MhO HF QUI Y I I I l Iy O 4 OJ 0.2 0.5 L0 2.0 3.0

' IN VENTORS NORIG TSUB UUCHI MA 5.4 0 TA KA HA SHI BY TOMEJI HNO TSUNEO AKASHI JM, W

TIORA/EYS' United States Patent O 3,544,471 PIEZOELECTRIC CERAMICS Norio Tsubouchi, Masao Takahashi, Tomeji Ohno, and Tsuneo Akashi, Tokyo, Japan, assignors to Nippon Electric Company, Limited, Tokyo, Japan Continuation-in-part of application Ser. No. 721,810, Apr. 16, 1968. This application July 9, 1969, Ser. No. 840,262 Claims priority, application Japan, Apr. 20, 1967, 42/56,173, 42/56,174 Int. Cl. H04b 35/00 U.S. Cl. 252-62.9 9 Claims ABSTRACT F THE DISCLOSURE A piezoelectric ceramic is disclosed consisting essentially of a solid solution of the three components PbTiO3 and PbZrO3, wherein Z represents one element selected from the group consisting of Nb and Ta. Up to about 25 atom percent of Pb may be replaced by at least one element selected from the group consisting of Ba, Sr and Ca. The ceramic may have incorporated in it about 0.1 to 3.0 weight percent of MnO.

This application is a continuation-in-part of U.S. application Ser. No. 721,810 filed Apr. 16, 1968, now abandoned.

This invention relates to piezoelectric materials and, more particularly, to novel piezoelectric ceramics having excellent properties suitable for use in various fields.

One of the typical elds of application of piezoelectric materials is in the manufacture of transducers for transmitting and receiving ultrasonic waves. In such use, the electromechanical coupling factor is very important for evaluating in practice the properties of piezoelectric materials to be used. The electromechanical coupling factor is representative of the eiciency of transforming the electric oscillation into mechanical vibration and of conversely transforming the mechanical vibration into electrical oscillation, a high value thereof generally indicating better eiciency of interconversion, particularly for piezoelectric materials used in the manufacture of transducers.

Piezoelectric materials are evaluated in accordance with certain fundamental factors, such as dielectric loss, dielectric constant and the mechanical quality factor. With regard to piezoelectric materials used for transducers, it is preferred that the dielectric loss be small, that the desirable value of the dielectric constant be large or small depending on the electric loads, the mechanical quality factor being not so important.

The foregoing subject matter is described in detail in, for example, D. Berlincourt et al., Transducer Properties of Lead Titanate Zirconate Ceramics, IRE Transactions on Ultrasonic Engineering, February 1960, pp. 1-6 and in R. C. V. Macario, Design Data for Band-Pass Ladder Filters Employing Ceramic Resonators, Electronic Engineering, vol. 33, No. 3 (1961), pp. 171-177.

Another typical field of application of piezoelectric materials is in the manufacture of elements for ceramic filters. In such applications, it is necessary to provide an electromechanical coupling factor having an optimum 3,544,471 Patented Dec. l, 1970 value selected from a wide band ranging from an extremely great value to a very small one, it being desirable that the value of the mechanical quality factor be as large as possible. This fact is fully described in, for example, the paperof Macario referred to above. The 'mechanical quality factor is recprocally related to the energy consumed by the material during energy conversion, a large mechanical quality factor accounting for smaller energy consumption.

The transducer elements of mechanical filters provide still other important fields of application of piezoelectric ceramics. In this case, both the electromechanical coupling factor and the mechanical quality factor should desirably be as large as possible.

It is well known, however, that conventional piezoelectric ceramics, for example, barium titanate (BaTiOa) and lead titanate-zirconate [Pb(TiZr)O3] exhibit small electromechanical coupling factors and are generally not suitable for practical use. Improvement of this factor has been made only by way of incorporating various additional constituents into the ceramics.

The object of this invention is to provide novel piezoelectric ceramics exhibiting large electromechanical coupling factors.

Another object of this invention is to provide novel piezoelectric ceramics suited for use in certain fields, such as the manufacture of transducers for transmitting and receiving ultrasonic waves where a very large electromechanical coupling factor is required.

Another object of this invention is to provide piezoelectric ceramics having large values of both the electromechanical coupling factor and mechanical quality factor.

A still further object of this invention is to provide piezoelectric ceramics suited for use in fields involving, for example, the manufacture of elements for ceramic filters and transducer elements for mechanical filters, Where a large or broadly ranging electromechanical coupling factor and large mechanical quality factor are required.

This invention is based on the discovery that ceramic compositions may be produced consisting essentially of a solid solution of the system where Z represents an element selected from Nb and Ta, said ceramic exhibiting excellent piezoelectric activity and therefore having practical utility.

The above ceramic compositions contain lead (Pb) as a divalent metallic element and also titanium (Ti) and zirconium (Zr) as tetravalent metallic elements. Moreover, the element antimony (Sb) and an element selected from the group niobium (Nb) and tantalum (Ta) are so proportioned that they may be, as a whole, substantially equivalent to a tetravalent metallic element. The lead (Pb) in the above composition may be replaced by up to about 25 atom percent of at least one element selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca).

Where niobium (Nb) is selected for Z, the ceramic material is comprised of the components Pb1/2Nb1/2)O3PbTlO3PbZI`O3 the ternary system represented by the compositional formula [Pb(sbl/gNbl/g)O3]X[PbTO3]y[PbZI`O3]Z, Where x, y or z is the molecular ratio of each component and x+y+z=1.00. Ithas been found advantageous that the Y compositions for achieving eiective properties should preferably -be within the range determined -by the following combination of the molecular ratios x, y and z:

z y z Where tantalum (Ta) is selected for Z, the advantageous effective range of the ceramic compositions is given by the formula where n+y+z=1.00, as determined by the following combination of molecular ratios x, y and z:

I y z such as disclosed in U.S. Pat. No. 3,268,453 granted Aug. 23, 1966 to H. Ouchi et al. This conventional ceramic material by itself, however, does not improve the piezoelectn'c properties of previous PbTiO3-'PbZrO3 ceramics, and improved piezoelectric ceramic materials are obtained only by adding thereto at least one of oxides of the group manganese, cobalt, nickel, iron and chromium in amounts up to about 3 weight percent. In contrast, the

Pb Mzzl/2) O3PbTi03PbZIO3 compositions of this invention, where Z represents Nb or Ta, markedly improve the piezoelectric properties without the use of any additional constituent. This difference in improvement of piezoelectric properties between the conventional compositions and the novel compositions of this invention is, it is believed, due to the fact that the conventional compositions use magnesium (Mg), an ele` ment belonging to the Group II-A in the Periodic Table, in conjunction with a Group V-A element niobium (Nb), as ingredients, whereas, in the compositions of this invention a Group V-B element, antimony (Sb), is used in conjunction with a Group V-A element niobium (Nb) or tantalum (Ta).

y Excellent piezoelectric activities of the ceramic cornpositions of this invention will be apparent from the following more particular description of preferred examples of this invention, as illustrated in the accompanying drawings, wherein:

FIGS. 1 and 4 are the triangular compositional diagrams of the ternary system showing both the effective ranges of the compositions of this invention and the specific compositions of the examples;

FIGS. 2 and 5 are graphs showing the electromechanical coupling factors of both the conventional lead titanatezirconate ceramics and the ceramics of this invention as a function of compositional change of lead titanate and lead zirconate in both the ceramics;

FIGS. 3 and 6 are the phase diagrams of the ternary system of this invention; and

FIGS. 7 and 8 are graphs showing the electromechanical coupling factor and the mechanical quality factor of modified ceramics of this invention as a function of the amount of manganese oxide added; while:

FIGS. l, 2, 3 and 7 are for the novel ternary system Pb (Sb1/3Nb1'/3)O3PbTiO3PbZrO3 among the ceramic compositions of this invention; and

FIGS. 4, 5, 6 and 8 are for the novel ternary system Pb (Sb1/2Ta1/2)O3-PbTiO3-PbZrO3 among the ceramic compositions of this invention.

` EXAMPLES Powdered materials of lead monoxide (PbO), antimony sesquioxide (Sb203), niobium pentoxide (Nb205), titanium dioxide (TiOz), and zirconium dioxide (Zr02) were used as starting materials to obtainl the ceramics of this invention, unless otherwise stated. These powdered materials were weighed so as to provide nal specimens having the compositional proportions shown in Table 1. The above materials were moreover used together with manganese carbonate (MnCO3) to produce the same ceramics containing manganese monoxide (MnO), unless otherwise mentioned. These were weighed so that the nal specimens would be comprised of the Vbasic compositionhaving various proportions of molecular ratios x, y and z and manganese monoxide (MnO) in an amount from 0.1 to 3.0 weight percent as shown in Table 3. In addition, either `barium carbonate (BaCO3), strontium carbonate (SrCO3) or calcium carbonate (CaCO3) was added to each group of the above starting ceramics of this invention, unless otherwise stated. These powders were weighed so that the nal specimens would have the compositional proportions shown in Table 2.

`Also, the above materials plus manganese carbonate (MnC 03) were used to produce the same ceramics containing manganese monoxide (MnO), unless otherwise stated. 'I'hese were weighed to provide inalvspe'cimens having the basic compositions and manganese oxide as shown in Table 4. Besides, barium carbonate (BaCO3), either strontium carbonate (SrCO3) or calcium carbonate (CaCO3) was added to each group of the above starting materials to obtain the ceramics having the compositions shown in Table 6, except that u atom percent of lead (Pb) contained in the basic composition (having the molecular ratios x, y and z of the components Pb(Sb1/2Ta1/2)O3, PbTiO3 and PbZrO3) Was replaced byMe (Ba, Sr or Ca). In this instance, manganese carbonate (MnCO3) and barium, strontium or calcium carbonate (BaCO3, SrCO3 or CaCO3) were weighed calculatedon the basis of manganese monoxide (MnO) and barium, strontium or `calcium oxide (BaO, SrO or CaO), respectively.

In addition, the powders of lead monoxide, titanium dioxide and zirconium dioxide were weighed to provide the conventional lead titanate-zirconate ceramics having' the compositional proportions shown in Table 7.

The respective powders were mixed in a lball mill with distilled water. The mixed powders Were subjected to filtration, dried, crushed, then pre-sintered at 900 C. for one hour, and again crushed. Thereafter, the mixtures, with a small amount of distilled water being added thereto, were press-molded into discs of 20 mm. in diameter at a pressure of 700 kg./cm.2 and sintered in an atmosphere of lead monoxide (PbO) for one hour at a temperature between 1270 C. and 1310 C. 'I'he resulting ceramic discs were polished on both surfaces t0 the thickness of one millimeter, provided with silver electrodes on Iboth surfaces, and thereafter piezoelectrically activated through the polarization treatment at 100 C. for one hour under an applied D.C. electric field of 30 kv./cm. in the case where the Pb,(Sb1/2Nb1/2) O3 or Pb(Sb1/ZTa1/2) O3 content of the specimens exceeded 0.10. On the other hand, discs were activated at room temperature for one hour under an applied D.C. electric field of 40 kv./cm. for specimens whose Pb(Sb1/2Nlb1/2)O3 or Pb(Sb1/2Ta1/2)O3 had a content of 0.10 or less.

After the ceramic discs had been allowed to stand for 24 hours, the electromechanical coupling factor for the radial mode vibration (kr) and the mechanical quality factor (Qm) were measured to evaluate the piezoelectric activities. 'I'he measurement of these piezoelectric properties was made according to the LRE standard circuit. The value of kr was calculated by the resonant to antiresonant frequency method. T'he dielectric constant (e) and the dielectric loss y,(tan were also measured at a frequency of 1 kHz. at room temperature.

Tables 1 through 7 show typical results obtained. In the tables, the specimens are arranged according to the content of PbTiO3 and there are also listed several values of Curie temperature which were determined through measurement of temperature variation in the dielectric constant (e). The novel compositions of the specimens of Tables 1 and 2 are shown with black points in FIGS.

1 and 4, respectively, while the conventional compositions of the specimens of Table 7 are indicated by crosses in the same figures. In Tables 3 and 4, the specimens are arranged according to the Pb(Sb1/2Z1/2)O3 content ('Z is Nb or Ta) of the basic composition, while those containing the same basic composition are arranged according to increase in the amount of manganese oxide (MnO).

Comparison of the results forV the specimens Nos. 9 and 10 of Table 1 or specimens Nos. 5, 8 and 9 of Table 2 with those for the specimen No. 4 of Table 7 will reveal that the greatest kr values of the novel ceramics of this invention are far superior to the maximum kr value of the conventional lead titanatezirconate ceramics which have been known as the most excellent piezoelectric ceramic material. Moreover, comparison of the results n Table 1 or 2 with those in Table 7, particularly between the novel and conventional ceramics in which the ratios of the PbTiOs content and PbZrO3 content are similar to each other, will also reveal that the ceramics of this invention exhibit remarkably improved kr values. This latter fact will be more clearly understood from FIG. 2 or 5, wherein the thick line curve represents the kr values of the novel ceramic containing 0.05 of the component Pb(Sb1/2Nb1/2)O3 [vl-TIG. 2] or the component Bb(Sb1/2Ta1/2)O3 [FIG. 5], the varying content y of PbTiO3, and the remaining content of PbZrO3; While the iine line curve shows the k, values of conventional lead titanate-zirconate ceramics with varying content y Of TO3.

As is seen from the above, this invention provides markedly improved and useful piezoelectric ceramics having superior piezoelectric activities.

In the novel ceramics of the system Pb(Sb1/2Z1/2)O3 PbTiO3-.PbZrO3 (Z is Nb or Ta) of this invention, the superior piezoelectric activities as mentioned above are provided when the composition is represented by the formula:

a: y z

In cases where the Pb(Sb1/2Nb1/2)O3 or Pb(Sb1/2Ta1/2) O3 content is less than that falling Within the above-mentioned area, it is sometimes impossible to complete the sintering in the manufacture of ceramics and besides the piezoelectric activities of the ceramics obtained are generally inferior to or nearly equal to those of the conventional lead titanate-zirconate ceramics or, even if improved, not desirable for practical use. If the Pb(Sb1/2Z1/2)O3 (Z represents Nb or Ta) content is more than that falling within the above-mentioned area, accomplishment of the sintering is very diiicult and the ceramics obtained do not generally exhibit practicable piezoelectric properties. Where the PbTiO3 content is more than or less than the effective content falling within the above-mentioned area, the piezoelectric properties of the ceramics tend to deteriorate so as to make their use undesirable. Finally, in the case where the PbZrO3 content is less than the effective content falling within the above-mentioned area, it is diiiicult to complete the sintering, to carry out the polarization treatment and achieve the desired optimum results, and obtain a useful piezoelectric ceramic. Where the BbZrO3 content is more than the effective amount, the piezoelectric ceramic is generally not useful and exhibits markedly inferior piezoelectric properties.

In View of the above, it is advantageous to have the compositions of the ceramics of this invention fall within any of the areas specied above. These ceramics exhibit excellent piezoelectric activities and have a high Curie temperature, as shown in Tables 1 and 2. In addition, these piezoelectric activities are not lost when heated to elevated temperatures.

The ternary system of Pb(Sb1/2Nb1/2)O3 or of this invention exists in a solid solution over a large portion of the compositions. Such solid solutions have a perovskite-type crystalline structure. FIGS. 3 and 6 show the crystalline phases of the ceramic compositions falling within the area A-BCDE of FIG. 1 and F-G-H-I- J-K of FIG. 4, respectively, as determined at room ternperature by the powder method of X-ray analysis. These compositions have a perovskite-type crystalline structure and belong to either the tetragonal phase (indicated by T. in the figures) or the rhombohedral phase (indicated by R). The morphotropic'phase boundary is shown with a thick line in each figure. In general, the value of kr is remarkably high'tor the compositions in the vicinity of this phase boundary, while the Q1n value is large forthe compositions remote from this boundary.V

Tables 3 and 4 reveal that incorporation of about 0.10 to 3.0 wt. percent MnO to the basic-compositions and Pb(Sb1/2Ta1/2)03-PbTiO3PbZrO3 results in an increased or widely ranged value of kr and a sharply enhanced value of Qm.`In other words, such incorporation provides excellentmaterial for use in the elements of ceramic filters, the transducer elements of mechanical filters or other fields where a high or widely ranging kr posed Vat elevated temperature to form manganese oxide. If-manganese compound other than` MnO` is utilized, it

, should be used in an equivalent amount as calculated on ly used instead of MnO. Where MnO is used, it is exemand a large Qm are both required. FIGS. 7 and 8 show i the relation between the content a of MnO and the resultant piezoelectric properties (kr and Qm) in specimens Nos. l to 16 of Table 3v and Nos. 5l to 57 of Table 4, respectively, as representative examples. It will be clearly seen from FIGS. 7 and 8 that excellent piezoelectric properties are obtainable ifthe content of MnO lies Within a range from 0.10 to 3.0 weight percent.

Where the MnO content is less than 0.10 wt. percent, little improvement of piezoelectric properties is achieved. If the MnO content exceeds 3.0 wt. percent, Qm decreases considerably and it becomes `diiiicult to obtain a uniform solid solution of the additive agent and the basic composition and to accomplish` the polarization treatment. Thus, the effective range of the MnOv content is defined from about 0.10 to 3.0 wt. percent. If the basic compositions do not fall within the above-mentioned areas A-B-C-D-E and F-G-H-I-J-K, the resultant ceramic possess rather inferior piezoelectric properties.

Tables and 6 reveal that excellent piezoelectric properties are still possessed by the ceramics in which a part of Pb of the basic composition is replaced by one of the elements Ba,.Sr or Ca. In general, at least one of Vthe elements Ba, Sr and Ca may replace up to about 25 atom percent of Pb contained inthe basic composition.

It should be noted here that the improvement made in the piezoelectric properties by incorporation of MnO clearly results from presence of manganese ions. There are'various known methods for introducing manganese ions into presence. For example, manganese ions may be put into existence by using as a starting material manganese oxide itself such as MnO or MnO2 or other manganese comopund such as MnCO3 which is easily decominclude appropriate additives.

plied in the specimens with double asterisks in Tables 3A- and 4.. v -It will be apparent that the starting materials to be used in the manufacture of'the ceramics of this invention are not limited tothose used in the above examples. It is found that those oxides may be usedwhich are easily. decomposed at elevated Vtemperautre to form requiredv compositions, as exemplifiedby the use of Pb304 to produce PbO inthe examples. Also, thoseV salts such as oxa.-A lates or carbonates may be usedin place of the oxides used in the examples, as these are easily decomposed into the respective oxides lat elevatedtemperature. In addition, hydroxides of the same character as above, such as Nb(OH)5, may be used instead of the oxides such as Nb205. As will be appreciated, excellent piezoelectric ceramics having similar properties to the above examples may also be obtained by preparing separately the powdered material of each of the components or Pb(Sb1/2Ta1/2)O3,V PbTiO3 and PbZrO3 in advance and by using them as starting materials for subsequent mixing.

It is usual for `niobium pentoxide (Nb205), tantalum pentoxide (Ta205) and zirconium dioxide (ZrOz) which are available in the market contain several percent of tantalumrpentoxide (Ta205), niobium pentoxide (Nb205) and hafnium dioxide (Hf02), respectively. Accordingly, the ceramic compositions of this invention are allowed to contain small amounts of these oxides or elements existing in the materials available in the market. Moreover, it is appreciated that the incorporation of a small amount of another agent in addition to or other than manganese oxide to the ceramic compositions o f this in-` vention may further improve the piezoelectric properties, similarly as recognized in the conventional lead titanatezirconate ceramics. It will be understood from the foregoing that the ceramic compositions of this invention may While there have rbeen described `what at present are believed to be the preferred examples of this invention, it will be obvious that various modifications can be made therein without departing from the scope of this inven-A tion and that` this inventionv covers all the ceramic compositions as specified in the appended claims.

TABLE 1 Mol ratio of composition Curie temper- Pb (SbkNbl/) Oa PbTiOs PbZrOa kr, tan ature Number a: y z percent Qm e percent C 0. 10 0. 70 0. 20 7 180 345 4. 7 0. 05 0. 65 0. 30 27 245 430 1. 9 0. 01 0. 61 0. 38 25 180 500 2. 8 0. 05 0. 55 0. 40 41 120 660 2. 2 0.=01 0. 48 0. 51 72 90 1, 680 2. 6 0. 05 0. 48 0. 47 57 Y 100 1, 610 2. 4 0. 10 0. 48 0. 42 34 150 1, 030y 2. 3 0. 20 0.48 0. 32 13 280 400 2. 5 0. 02 0.47 0. 51 81 85 1, 760 2. 6 0.05 0.455 0 495 67 85 1,310 3.0 0. 10 0. 45 0. 45 39 125 1, 245 2. 5 0. 10 0. 43 0.47 46 110 1, 310 2:9 0. 05 0. 40 0. 55 52 115 760 3. 7 0. 05 0. 30 0. 65 39 130 580 3. 7 0. 10 0. 30 0. 60 33 215 655 3. 6 0. 30 0. 30 0. 40 8 170 530 3. 5 0. 05 Y 0. 20 0. 75 28 300 460 3. 7 0. 20 0. 20 0. 60 6 320 330 2. 8 O. 0l 0. 09 0. 90 15 500 290 4. 3 0. 05 0. 05 0 90 13 360 390 4. 2

* See footnote to Table 2.

TABLE 2 Mol ratio of composition Curie temper- Pb (Sb1/2Nb1/z)0a PbTiOs PbZrOa kr, tan ature, :c y z percent Qm e percent C.

Nora-In the manufacture of the specimens whose Nos. have an asterisk in Tables 1 and 2, triplumbic tetroxide (Pb204) was used instead of lead monoxide (PbO) as one of the starting materials. In the manufacture of specimens with double asterisks manganese dioxide (Mn02) was used instead of manganese carbonate as one of the starting materials.

TABLE 3 Mol ratio ot basic composition Additiv agen Pb(Sb1/1Nb1/2)O; PbTiO; PbZrO MnO, wt. kr, tan 5, :c 1l z percent percent Qm e percent 0. 30 D. 30 0. 40 0. 00 8 170 530 3. 5 0. 30 0. 30 0. 40 0. 10 8 390 490 1. 2 0. 30 0. 30 0. 40 0. 50 9 2, 270 420 1. 1 0. 30 0. 30 0. 40 3. 00 5 650 380 3. 1 0. 10 0. 30 D. 60 0. 00 33 215 655 3. 6 0. 10 0. 30 0. 60 0. 10 33 330 600 1. 1 0. 10 0. 30 0. 60 0. 20 36 1, 370 310 0. 8 0. 10 0. 30 0. 60 0. 50 34 3, 480 440 0. 8 0. 10 0. 30 0. 60 1. 00 36 3, 160 400 0. 8 0. 10 0. 43 0. 42 0. 00 34 150 1, 030 2. 3 0. 10 0. 48 0. 42 0. 10 26 300 680 1. 2 0. 10 0. 48 0. 42 0. 20 30 850 660 0. 8 0. 10 0. 48 0. 42 0. 50 41 1, 920 900 1. 0 0110 0. 4B 0. 42 1. 0 48 1, 660 1, 070 1. 5 0. 10 0. 48 0. 42 2. 0 45 1, 040 890 1. 8 0. 10 0. 48 0. 42 3. 0 35 0 760 2. 0 0. 10 0. 70 0.20 0. 00 7 180 345 4. 7 0. 10 0. 70 0. 20 0. 10 7 390 300 1. 5 0. 10 0. 70 0. 20 0. 50 8 1., 580 260 1. 3 0. 10 0. 70 0. 20 3. 0 5 610 230 3. 6 0. 05 0. 05 0. 90 0. 00 13 360 390 4. 2 0. 05 0. 05 0. 90 0. 10 11 720 350 1. 2 0. 05 0. 05 0. 90 0. 50 10 1, 750 330 1. 1 0. 05 0. 05 0. 90 3. 0 5 760 320 3. 5 0. 05 0. 20 0. 75 0. 00 28 300 460 3. 7 0. 05 0. 20 0. 75 0. 10 24 480 400 0. 8 0. 05 0. 20 0. 75 0. 20 24 910 410 1. 0 0. 05 0. 20 0. 75 0. 50 24 2, 480 340 1. 2 0. 05 0. 20 0. 75 1. 0 24 2, 980 340 1. 1 0. 05 0. 20 0. 75 2. 0 22 2, 000 320 1. 5 0. 05 0. 20 0. 75 3. 0 18 1, 180 290 2. 0 0. 05 0. 40 0. 55 0. 00 52 115 760 3. 7 0. 05 0. 40 0. 55 0. 10 51 290 670 1. 5 0. 05 0. 40 0. 55 0. 20 46 860 540 1. 0 0. 05 0. 40 0. 55 0. 50 45 2, 440 420 1. 0 0. 05 0. 40 0. 55 1. 0 37 1, 580 350 2. 3 0. 05 0. 40 0. 55 2. 0 31 1, 210 330 2. 6 0. 05 0. 40 0. 55 3. 0 28 1, 000 310 3. 0 0. 05 0. 48 0. 47 0. 00 57 100 1, 610 2. 4 0. 05 0. 48 0. 47 O. 10 38 220 1, 170 1. 1 0. 05 0. 48 0. 47 0. 20 42 580 1, 130 1. 0 0. 05 0. 48 0. 47 0. 50 58 2, 200 1, 150 0. 9 0. 05 0. 48 0. 47 1. 0 48 620 1, 130 l. 3 0. 05 0. 55 0. 40 0. 00 41 120 660 2. 2 9. 05 0. 55 0. 40 9. 10 23 340 630 0. 9 0. 05 0. 55 0. 40 0. 20 25 1, 380 550 0. 9 0. 05 0. 55 0. 40 0. 50 36 3, 560 620 0. 8 0. 05 0. 55 0. 40 1. 0 23 1, 910 460 1. 3 0. 05 0. 55 0. 40 2. 0 23 1, 180 390 1. 9 0. 05 0. 55 O. 49 3. 0 21 860 349 2. 2 0. 02 0. 47 0. 61 0. 00 81 85 1, 760 2. 6 0. 02 0. 47 0. 51 0. 10 47 430 1, 120 1. 1 0. 02 0. 47 0. 51 0. 20 54 1, 630 8 0. 9 0. 02 0. 47 0. 51 0. 30 69 1, 660 790 0. 9 0. 02 0. 47 0. 51 0. 50 58 800 740 1. 2 0. 02 0. 47 0. 51 1. O 48 640 500 1. 8 0. 02 0. 47 0. 51 2. 0 42 450 460 2. 1 0. 02 0. 47 0. 51 3. 0 41 310 410 2. 5 0. 01 0. 09 0. 90 0. 00 15 500 290 4. 3 0. 01 0. 09 0. 90 0. 10 13 810 260 1. 1 0. 01 0. 09 0. 90 O. 50 12 1, 830 230 1. 1 0. 01 0. 09 O. 90 3. 0 6 880 220 3. 2 0. 01 0. 61 0. 38 0. 00 25 180 500 2. 8 0. 01 0. 61 0. 38 0. 10 22 380 400 1. 1 0. 01 0. 61 0. 38 0. 50 22 2, 360 350 1. 0 0. 01 0. 61 0. 38 3. 0 18 1, 120 290 2. 5

See footnote to Table 2.

tan percent' Additive agent MnO, wt.

PbZrOa kr, y z percent percent Number 55550 000000000000 000000000000033333 555 0 055555 5555 00003 333334444222 244444441111144444 000%3w333333-mmmMUMW-MwMMM 0.0.0.0.0.0.0.0.0.000.00.00000000000000000000000000000000000000000000000000000000000000000000 000000 00000 0000000000 0000000005 555 5555555 5555 333333mwm33333 222222222o/.www1111111110%000M0000000%0000%%%%%%%%%%%%Wmmmmmmmmmmm 0.0.0.0000000000000000000000000000000000000000000000000000000000000000000000000000000 See footnote to Table 2.

kh percent percent Basic composition i tan 5, percent MnO, Wt.

912560355L30 2.LL2.2.LL2.ZLL2.

0 0 wmmwmmswmwsm 0.0.0. .0.0.0. .0.0.0.

Pb(Sb1/2Nb1/2) Oa-PbTiOa-PbZrOa SYSTEM TABLE 5.-Continued MnO,

wt percent percent Basic composition tan percent 00.0000000000000000000000QQQ0QQQQ000 KATABLE e Pb (sbl/fram) os-PbTioa-Pbzroa' SYSTEM Basic composition tan e percent .g Wt. kr, percent percent 712772258599723672358256928582771 883800 211221123MLLZ2LL2ZLL2ZLL22LLZZLL2&1L2&LZ&

aaaaaaaaaaaarrrraaaarrrraaaarrrraaaarrrr BBBBBBBBBBBBSSSSCCCCSSSSCCCCSSSSCCCCSSSS 22220000 11111 0000111i%%00oommmwwwwwwwww oo w O00000000QQQQ0QQOWQQQQQQQQ000000000000000 @0.0.0.0QQQQQQQQQQnwQQQQQQQQQ0QQQQQQQQQQQQQQ 222222222222222222 22222222 2 2 22 00000000000000OOOWOOOOOOWMOWWWWMOWOO 00.000aa00a@QaQQnmQQQQQQQQQQQUWQQQQQQQQQQQ What is claimed is:

TABLE 7 Mol ratio of composition 65 1. Piezoelectric ceramics consisting essentially of the petrlxf composition which is represented by the formula kr, PbTiOa PbZrOa percent NoTE.-For the specimens Nos. land 2, the evaluation of piezoelectric FlG: 1 0f the drawings Where Nb is Selected fOI' Z 21nd activities was not posslble- 75 within the area F-G-H-I-J-K of FIG. 4 of the drawings of the vertices of said areas being as follows:

a: y z

A 0. 01 0. 61 0. 38 B 0. 01 0. 09 0. 90 C 0. 05 0. 05 0. 90 D 0. 30 0. 30 0. 40 E 0. 0. 70 0. 20 F 0. 01 0. 55 0. 44 G 0. 01 0. 09 0. 90 H 0. 05 0. 05 0. 90 I 0. 30 0. 05 0. 65 J 0. 30 0. 40 0. 30 K 0. 05 0. 65 0. 30

2. The piezoelectric ceramics of claim 1, wherein up to about 25 atom percent of Pb is replaced by at least one element from the group consisting of Ba, Sr and Ca.

3. The piezoelectric ceramicsof claim 1, wherein man'- ganese oxide is incorporated in an amount of about 0.10 to 3.0 weight percent in the form of MnO.

4. The piezoelectric ceramics `of claim 1, wherein Z is Nb, and wherein the composition falls within the area A-B-C-D-E of FIG. 1 of the drawings, the sets of molecular ratios of the vertices of said area being as follows:

:c y z one element from the group consisting of Ba, Sr and Ca.v l, 1061-39` 6. The piezoelectric ceramics of claim 4, wherein manganese oxide is incorporated in an amount of about 0.10 to 3.0 weight percent in the form of MnO. 1 I

7.Y The piezoelectric ceramic o f claiml 1, wherein Z is 'Ta, and wherein the compositionfalls within the area F-G-H-I-I-K of FIG. 4 of the drawings, the sets of molecular ratios of the vertices of said areas being as follows:

F 0.01 0.55 0.44 G 0. 01 o. 09 o, 90 H 0. 05 0. o5 0. 90 r 0. 0. o5 0. es J 0. 30 0. 4o 0.30 K 0.05 o. 0. a0

8. The piezoelectric ceramic of claim 7, wherein up to about 25 atom percent of Pbis replaced by at least one element from the group consisting of-Ba, Sr and Ca.

9. 'I'he piezoelectric ceramic of claim 7, wherein manganese oxide is incorporated in an amount of about 0.10 to 3.0 weight percent in the form of MnO.

References Cited UNITED STATES PATENTS 3,424,686 1/ 1969 Ouchi et al. 252-629 3,425,944 2/ 1969 Ouchi etal.l 252-629 3,468,800 9/ 1969 Yokoyama et al. 252-623 l 'roBrAs E. LEvoW,v Primary Examiner J. COOPER, Assistant Examiner

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